The sink cover in my Bambi II was made of laminated plywood. Never tried to use as a cutting board, just soft wood. The cover on my Safari is made from heavy duty plastic/polyurethane. I use it as a cutting board regularly.

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__________________MICHAEL

Do you know what a learning experience is? A learning experience is one of those things that says "You know that thing that you just did? Don't do that."

Generally they're heavy due to thickness and particle board, they're same as countertop. So would you use that as cutting board , you can but expect them to get cut up, also not made to be easily sanitized/washed.
They're meant to provide extra counter space when not using the sink.
Do not leave them in the sink during travel, they have a very high tendency to become projectiles that cause damage.

I WON'T use the inserts as cutting boards then, and will buy a dedicated cutting board for my chopping and slicing needs. At some point, I may replace one or both inserts with cutting boards, though, which would be a fun project and look pretty.

Related to this: do you guys know of a good supplier for sink cover replacements? I have an '89 Squargosy with no sink covers and would love them so I can have more counter space. Thank you for any info!